get authors of all network sites

network-authors.php

<?php

// update: this code seems to work now

require('/home/username/public_html/wp-load.php');

$list = get_blog_list( 0, 'all' );

foreach ($list as $site) {
        switch_to_blog( $site["blog_id"] );
        echo $site["path"] . "<br />";
        echo "<ul>";
                wp_list_authors('hide_empty=0');
        echo "</ul>";
}